This invention relates to novel compositions of the formula Na0.5M0.5Cu3Ti4O12 wherein M is Laxe2x80x94Lu, Y, Bi or mixtures thereof.
The use of dielectric materials to increase capacitance is well known and long-used. Known capacitor dielectrics fall into two categories. One category of dielectrics has a relatively temperature-independent dielectric constant but the value of the dielectric constant is low, e.g. 5-10. Materials such as electrical porcelain and mica fall into this category. Another category of dielectrics has a very high dielectric constant, e.g. 1000 or more, but they are quite frequency dependent. An example is barium titanate (BaTiO3).
Since the capacitance is proportional to the dielectric constant, high dielectric constant materials are desired. In order to perform acceptably in electronic circuits, the dielectric must have a dielectric constant that exhibits minimal frequency dependence. It is also desirable to have the loss or dissipation factor as small as possible. The materials of this invention meets those needs.
This invention provides compositions of the formula Na0.5M0.5Cu3Ti4O12 wherein M is Laxe2x80x94Lu, Y, Bi or mixtures thereof. These compositions have high dielectric constant and low loss over a frequency range of from 1 kHz to 1 MHz and are especially useful in capacitors in electronic devices such as phase shifters, matching networks, oscillators, filters, resonators, and antennas comprising interdigital and trilayer capacitors, coplanar waveguides and microstrips.